System for classifying, concentrating, and separating ores



Nov. 18, 1952 v, RAWUNGS 2 ,618,388

' SYSTEM FOR CLASSIFYING, CONCENTRATING, AND SEPARATING ORES Filed Nov.6, 1947 7' 7 Sheets-Sheet 1 INVENTOR.

Nov. 18, 1952 J. v. RAWLINGS 2,618,388

SYSTEM FOR CLASSIF'YING, CONCENTRATING, AND SEPARATING ORES Filed Nov.6, 194'! '7 Sheets-Sheet 2 IN V EN TOR.

(M 1! RA WL/NGS 7 Nov. 18, 1952 I J. v. RAWLINGS 2,618,388

SYSTEM FOR CLASSIFYING, CONCENTRATING, AND SEPARATING ORES Filed Nov. 6,1947 7 Sheets-Sheet 3 Fzy 3. I

IN VEN TOR.

JACK 1 RAWU/VGS NOV. 18, 1952 v, RA 2,618,388

SYSTEM FOR CLASSIFYING, CONCENTRATING, AN-D SEPARATING ORES 7Sheets-Sheet 4 Filed Nov. 6, i947 IN VEN TOR.

75 #mgkmwumes Nov- 1952 I J. v. RAWLINGS ,3 8

SYSTEM FOR CLASSIF'YING, CONCENTRATING, AND SEPARATING ORES Filed Nov.6, 194'7v 7 Sheets-Sheet 5 Y M p INVENTOIVQ.

Nov. 18, 1952 v RAWUNGS 2,618,388

SYSTEM FOR CLASSIFYING, CONCENTRATING, AND SEPARATING ORES Filed Nov. e,1947 7 Sheets-Sheet 6 IN V EN TOR.

Mag. 1/. FAWN/V65 Nov. 18, 1952 J. v. RAWLINGS 2,518,338

SYSTEM FOR CLASSIFYING, CONCENTRATING, AND SEPARATING ORES Filed Nov. e,1947 7 Sheets-Sheet 7 Patented Nov. 18, 1952 SYSTEM FOR CLASSIFYING,CONCENTRAT- ING, AND SEPARATING ORES Jack V. Rawlings, Contact, Nev.,assignor of onehalf to Loretta P. McLean, Contact, Nev.

Application November 6, 1947, Serial No. 784,446

11 Claims. 1

This invention relates to a system for classifying, concentrating andseparating ores.

In prior practice, these operations are performed in various ways, manydifferent methods having been developed for producing these effects,these generally having been more or less individualized so as to providethese operations as individuals rather than the result ofa singleoperation. In some instances, the operations are more or less of amechanical type provided by special forms of apparatus, the modernpractice, however, tending more in the direction of the use of what areknown as flotation methods for providing some of the activities that areinherently required for the efiicient action of a plant devoted to thepurpose of obtaining the mineral values of the ores being handled.

As a result, the plant requirements for an efficient development becomevery large and expensive, both in cost of installation and foroperation, especially where the flotation methods are being employed.Hence, such plants generally operate in connection with ores in whichthe mineral content is of sufficient value to justify the cost ofoperation, the ores of less value being cast aside, due to the fact thatthe values which would be obtained therefrom are comparatively smallandv would therefore not justify their treatment, since the. cost wouldexceed the returns which could be obtained in disposing of the product.

While the presentinvention is not limited in its service to thetreatment of ores of such rejected type, the invention is such as tomake possible the. treatment of many of these rejected ores, since thecost of operation is sufiiciently low'as to justify the treatment of agreat many .or such rejected ores. In practice, a system of the type ofthe present single apparatus which may be made up of a single unit or ofa succession of units in which the product of one unit can form thesupply-for a similar vunit'into which a product of the first unit isdelivered. For instance, where the ore is of simple type, a single unitmay be sufficient for the treatment; where the ores are complex,additional units may be employed, with the initial unit active toseparate a mineral from the initial supply, with the remainder rejectedand forming the basis for the separating action of a second unit; or theproduct of the first unit may be made up of a pair of minerals andthese, then. separated Within a unit to which the product isdelivered-with highlycomplex ores this practice may be developed to anextent where the initial unit separation is a rough classification withthe products then subjected to the actionof second stage of units andeven to a third stage of units dealing with the products of the secondstage.

The invention which forms the basis of 'the system herein disclosed, isin the form of one or more similar units each of which is designed toprovide for the classifying, concentrating and separation of the contentwhich initially was in the form of a pulp made up of finely ground oreand a water carrier. The unit in operation treats increments of suchpulp by subjecting the increment content to a type of operation suchthat in the course of time and during continuous operation, there willbe a gradual concentration of a particular ore value or group of values,the concentration being grad al, with possibly a classification ofrejected values, making it possible to isolate particular values simplyby the unit in operation.

In this unit operation, several of the forces-of nature are utilized forthe purpose of producing the action. For instance, centrifugal force inan approximately infinite number of values is utilized; in addition, thequality of coefiicient of friction is made active in providing for theconcentration. These, in addition to speed variations of the unit, plusthe controlled use of water supplies, all provide for setting up anactivity upon the content of the pulp such that practically all of theindividual particles of the pulp are each acted upon during the unitoperation, with these actions effective to produce the classifying,concentrating and separating operation. With complex ores, a pluralityof units may be employed with the mineral products of the initial andmain unit then forming the supply for the operation of the succeedingunit or units, .the number of units depending somewhat upon thecharacter of the complex ores and the particular mineral values which itis desired to be isolated.

small particle having the proportionate valueprovided by the differencein size. Since these values become very small when the smallparticlesizeis produced through grinding of the ore, it is apparent that todistinguish between the particles of different metals by centrifugalforce activity, requires the use of infinite numbers of centrifugalforce values in orderto set up a dis tinguishing factor. The unit of thepresentsy-a' tem is designed in such way as to produce the infinity i.1 1. alues hat. s. eedd. q pr v e thi d s inguishing charact r s ihrqushm h han i struc ur p u t e nor al pe d ns which arc themselvescapable of being adj ste d, together with, the controllable use ofalignrd such as, water as a means for producing action within the unit,the active system will gradually produce the classifying, concentra ngand separating action.

The ccncentrationof' particles of a particular rnetal is brought about,by the fact that where two particles of the samemetal are broughtinto'actualjcontact, under pressures such as may be set -up throughcentrifugal force action, the similarity in texture between the two willserve to produce an approximate mating condition between the opposingsurfaces in contact; the variations, in'texture between metals are suchthat the variations which provide for difference in resistance betweencomponent parts; of the particle, cooperate to produce such matingcondition as the particles are moved relative to each other whileincontact in the operation of the apparatus; when this condition becomescomplete, there is set up the coefficient of friction value betweentheparticles that is to be found wheretwosimilar metals are brought intocontact'undcrconditions where friction may result, this valuedifferingwith different metals. The

particles are-not amalgamated in producing the concentration,- but theconcentrated mass is gradually developed through the accretion ofparticles gradually assembled through the unit operation and held intheir concentrated form by the coefficient of friction which isdeveloped as: the particles are added; to theconcentrated in? thepresence of the pressures which are set-upthrdughthe centrifugal forceconditions andwhich are present while the particles and the concentratedmass remain Within the active unit, the coefficient friction valuereferred to serying to hold the mass-in its concentrated form afterleaving the unit-.

1:9; theseand 'other; ends, therefore, the nature of-whiohwillybe betterunderstood asthe inventi n-is hcreinafter more fully disclosed,saidinventicnconsists in the methods and apparatus hcreinaften moreparticularly described in detail; illustrated in the accompanyingdrawings,

and more particularly pointed out in the appended claims.

In the accompanying drawings in which simil'arreference charactersindicate similar parts in each of the views;

' V Figura 1- is a View partly in side elevation and partly in verticalsection of a unit in accordance with the present invention; the viewincludes a section of the pul delivery structure, although thisstructure is, in fact, located at a point which would not be includedwithin this view, the structure being displaced from its actual positionin order to illustrate certain dimensional characteristicsrelative-toothen: portions of the unit.

Figure 2 is an end elevation of the structure of Fig. 1, the viewlooking toward the larger end of the drum;

Figure 3- is a vertical end View looking in the direction: of theopposite end of the drum.

Figure. 4, is a. vertical section, on an enlarged scale, sh owing;thedriving structure for the drum assembly.

Figure 5 is a partial horizontal section of the drum; zone, and showingmore particularly the arrangement of the water spray structure.

Figure 6 is a detail view, shown partially in section and partially inelevation of-on-e ofthe nozzles of the; spraying structure.

Figure'lis an end elevation looking-tqwardthe left in Fig. 6.

Figure 8 is an endelevation of the nozzle of Fig. 6 when viewed fromtheleft of said figure.

Figure 9 isa detail plan view showing; a portion of; two adjacentscrollriflle convolutions with their rifiles.

Figure 10 isa sectional view taken on line Hi -l ll of Figure 9'.

Figure 11 is a detail cross section taken on the line llH' ofFigure 9.

Figure 12 is a schematic view showing a battery of three units mountedin cooperative relation.

Figure 13 isa diagrammatic view showing'relative positions of 'the drumduring the revolution about the axis of revolution.

Figure 14 is a diagrammatic view designed to illustrate differences incentrifugal-force values within the active segment of thedrum, the-viewshowing thepaths of travel of' certain riiil'es' of a scrollconvolution, the-view indicating the paths for'the rifiles ofconvolutions at the larger and the smaller-endsof the drum.

Figure 15 is a schematic diagrammatic View of a drum segmentandi'showing characteristics of the riffle grooves of such segment; theView being designed more particularly. to illustrate: the relationshipin angularity of the sides of" the rifile grooves when passing towardand-through the active quadrant of 'thedrum.

The classifying, concentratingand separation activities of'a unittakeplacewithin theconical drum: 20 mountedifon movement about: an, axis,such movements serving'asaapart of the apparatus for producing theseactivities-,-not through a predetermined'regimenwith respect' to'jthepulp material but producing-theclassifying; concen trating andseparating actions; as; aresult: developed as the particles of "the-pulptraversefthe drum in the directions-of its endzones.

The drum 2-0 is-of' general conical; shape and open at'both ends.Its-internalface-yis provided with a. spirally arranged formation,herein-after broadlyvtermed a. scroll*'riflie; the general arrangement'. of the latterbeing indicated somewhat in Figure 1. Eachconvolution of the scroll rifile differs slightly. from" the-adjacentconvolution, each convolution, however, being of general triangularcross section of the isosceles type as indicated somewhatinFigure l0,the.base of the convolution. being secured; to the inner: face: 01

the drum, the inclined sides of the convolution meeting substantiallymidway of the length of the base-width of the convolution-to provide theapex 22a of a convolution 22 of the scroll rifiie 2|; as particularlyshown in Figure 1, the width of the base portion of the convolutiongradually increases toward the smaller end of the drum, with thealtitude represented by the apex 22a gradually being reduced in height,thus providing for a gradual change in characteristics of the scrollfrom that shown at the larger end of the drum to that shown at thesmaller end.

Each of the side faces of the convolution is provided with rifiles 23,these being in the form of grooves, which, in practice have their lengthextending at an angle of approximately 45 degrees from a line whichrepresents the anex of the convolution. The length of a groove 23a ofriflie 23 is such as to be included within the width of the side onwhich it is located-being less than such width-a cross section of thegroove see Figure 11showing the groove as of V-shape in cross section,the angularity of the sides being approximately 45 degrees from thevertical. The groove depth is greatest in a vertical plane through theapex of the convolution, the dimensions of the groove decreasing in adirection away from such plane until the groove disappears at a point onthe side face spaced from the end of the base. Since the side faceextends angular to the base, this arrangement of the groove causes thebottom 23b of the groove to extend angular to both the angle of the sideface and of the base. As is apparent, the difference in angularity ofthe side faces of the several convolutions causes the bottom of thegroove of the rifiies to become less angular to the base in thedirection of the smaller end of the drum; in practice, the riffles inthe end zone of the smaller end of the drum tend to approach parallelismwith the base. In other words, the riflies grow steeper in type in thedirection of the larger end of the drum.

The riffies 23 on one of the side faces of the convolution are spacedrelative to each other, with the rifiles of the opposite side faceopposed to such space between riflles--in other words, the rifiles ofthe opposite side faces of a convolution are staggered with respect toeach other, but extend in the same general direction relative to theplane of the travel path of the inner end of each riflie with theangularity to such paths be-- ing generally similar but opposite indirection, so that the length direction of all of the rifiles isuniformly similar, the groove 23a of one side face extending in the samegeneral direction as the adjacent groove of the other side face withgrooves of the two faces extending at opposite angles to such travelpaths of the groove inner ends. This construction renders it somewhatdiflicult to provide the proper machining operation for the productionof the grooves and for this reason, the convolution is practicallyformed in two halves with the dividing line corresponding a verticalplane through the apex, thus permitting each half to be machined withthe cutting tool moving from the deeper end of the groove to itsdisappearing point. The two halves are then secured together in suitablemanner, as by welding or the like.

The drum 26 is mounted for movement relative to an axis of revolutionand the drum is so mounted that the drum axis is not alined with suchaxis of revolution but extends parallel there to so that the drum axistravels in a circular orbitalzpath' about such axis of revolution. In

practice, the drum axis is spaced from the axis of revolution a distanceof approximately inch, so that the circular path of the drum axis isapproximately 1 /2 inchesin diameter. This particular distance is,however, more or less illustrative, since it may be varied to meetindividual conditions.

To obtain this off-center condition of the drum, the smaller end of thedrum is supported on the shaft 24 by arms 25, two of which are shown inFigure 1, the arms being of different length, the difference in lengthproviding for positioning this end of the drum in its off-centerposition.

The larger end of the drum is supported by a structure 26 carrying apair of supporting memb'ers 21, the upper end of each of which carries aroller 21a, members 21 being located equidistant from a vertical planeextending through such axis of revolution. The drum itself carries atrack 28, the peripheral face of which is adapted to rest upon and rideon the rollers 21a. However, while the track periphery is circular incontour with the axis of such face coincident with the axis ofrevolution, the track is so formed as to mount the drum with the drumaxis offset from such axis of revolution the distance referred to, thusproviding the parallelism between the drum axis and such axis ofrevolution. As a result, the radial depth of the track outside of thedrum varies due to the eccentric mounting of the drum within such track,it being understood, of course, that the eccentricity of this end of thedrum is exactly similar to the eccentricity provided at the oppositeend, so that the drum axis throughout the drum length will travel in thecircular path about the axis of revolution referred to above.

This drum mounting is important and in Figure 13, it can be readily seenthat when the track is positioned so that its larger external radiusextends on a vertical plane through the axis of revolution and below thedrum, the diametrically opposite portion of the track will extend onsuch plane but have the least external length of radius; at such time,the external radius of the track on a horizontal plane extending throughthe axis of revolution will be of intermediate length and uniform on theopposite sides. As the track rotates around the axis of revolution, thiscondition as to the relative lengths of the external radius of the trackwill continue but with a constantly changing position-in other words,the conditions pointed out above will be rotated bodily about the axisof revolution.

This arrangement sets up a particular condition with respect to therifl'les '23. For instance, a rifile located at the bottom of the drumwhen the track is in the full lines position of Figure 13, will advancein a truly circular path about the axis of revolution; at the same time,a riflle which would be located at the top of the drum and on thevertical plane through the axis of revolution, would also advancethrough a circular path about the axis of revolution, but the two pathswould be concentric and separated a distance equal to the amount ofeccentricity provided by the particular mounting. Obviously, riiileswhich are located between these two riffles (which are assumed to be onthe vertical plane referred to) also travel in circular paths about theaxis of revolution, but these paths would not be coincident butconcentric, due to the fact that each is located in a track zone ofdifferent external radial length from those of adjacent riflles. Inother words, each rifile travels in' a circular path about1th'eeaxiszofrevol'utiom but, dueato' the eccentricity ofthe drum relativeto such:axis" of revolution, the diameters and the peripherallength. of thedifferent travel paths will differ: as between adjacent rifiies, 1although thediiference may be slight.

The effects produced by this structure in service are. of severaldifferent types; one of these is'illustrated diagrammatically in Figure14. As presently pointed out, the actual activities of the drum in theway of producing the combined actions referred to upon the ore content,are practically confined to a 90 degree portion of the revolution of,the drum-this range extending fromthe nadir point of the drum path to amid positionin the'upward travel of the drum in the directioncf. such.path; the-ore pulp isdelivered to the drum preceding such nadir point inthe direction'lof travel of the drum, but theclassifying; concentratingand separating action has its beginning at such nadir point. Hence,Figure, 14 is-restricted to the quadrant of revolution of the druminwhich this activity takes place.

"In-Figure 14, windicates the axis of revolution, with the several linesshown indicating the respective'travelpaths of several of the riffles tobe found onan inclined face of a convolution of the'scroll. Forinstance, referring to Figures 1 and 14, the line b'will indicate thetravel path through this zone of the rifile carried by the outer face ofthe scroll convolution at the larger end of the drum, the particularriffie being that shown at the bottom of Figure 1; line will indicatethe travel path of the riiile diametrically opposite that referredto-shown at the top of Figure 1 and which would be rotated to the nadirposition when the drum has moved through half its travel path-when suchrifiie is thus made active within this particular zone; line at wouldrepresent the travel path of a rifile positioned midway between thesetwo rifiles, when such rifile reaches the nadir point; lines 6 and 1represent travel paths of rifiles intermediate the threeriffles-referred to. Lines 1), c", d, e and f represent correspondingtravel paths of the rifiles of the outer face of the scroll convolutionpositioned at the smaller end of the drum and which, since the drum ismoved bodily about the axis ofrevolution, will have their periods ofactivities within the-same quadrant.

It maybe noted that these lines of the diagram do not present concurrentactivity within the quadrant zone. For instance, the riflle having thetravel path 0 is at the top of the drum at the time the riille producingthe travel path indicated as his becoming active within the quadrant, sothat the travel path 0 would become-active only at a later period. Inother words, during activity of the rifile' traveling the line b path,only the riflie producing the line 1 path would become activeconcurrently with that producing lineb and then only afterthe rifile ofline 22 had advanced about halfthe' length of its travel path within thequadrant; the riifle producing line 03 would become active'at the nadirpoint only as the riiile of line b is passing out of the quadrant; theriiiles producing lines o and e would be inactive in the quadrant whilethe riffie of line b is active. Similar conditions, of course, applywith respect to the lines b to f. In either case, however, the riffleshaving the travel paths indicated will traverse; this quadrant at sometime during the revolutionlof the-drum inits path.

While the path of; travel of only five; of ,the

,rifilesdsshown-in Figure 14, it willbe understood that each of. therifliescontained on the outer side face of such convolution" atthe-larger. end of the drum will produce its individual path". oftravel, with such path lying between 1ines-.-b and 0, these individualpathsbeing due to the eccentric mounting of the drum relative'to' theaxisz-of revolution; Hence; within the zone between :lines band 0', willbe found a number of'such' concentric paths equal to thenumber'ofrifliestha-t are found in one half the length of suchconvolution face, with each-rifiie traveling its individualpath throughthe quadrant at some time during-zthe revolution of the drum initsipathrThe abovedescription of'Figure 14refersmore particularly to therifllescarriedbytheouter face of the end convolution. of the largerend'of. the drum, so far asconcerns-v the rifllesrof suchv face found onthe omitted portion of. Figure: 1, the rifiies referred to being-thosecontainediwithin degrees of the circumference ofthedrum; the descriptionindicating that linev b represents th'e path of travel of the riiiie atthe nadir point in Figure 1. Since the drum is mounted eccentric to theaxis of revolution a, the-rifllesicarried-by the remainder of theconvolution circumference will provide similar activities exceptingthat-. the order of the riflies reachingthe nadir point-will bereversed. For instance;- when the rifiie at the top of Figure 1 reachesthe nadir pointand begins its travel in the path of line- 0, thesucceeding riille to reach the nadir point would have the slightlysmaller radius that was. present with the rilfle preceding therifilewhich produces the travel path 0, while the succeeding rifilewould provide a still smaller radial length, etc., thus reversing theconditions which were referred'to above as ranging from the path I) tothe path 0.

In other words, the lines b-c represent aband of individual riiiietravel paths-which, basedon the showing of Figure 1, would havethe-nadir point rifile on line b, the riflies successively reaching thispoint with increasing radii until the ,half revolution brings the activeline as line 0, thus traversing'this band from-line b to line 0. As thedrum continues to move in its orbital path, the direction of travelthrough this-band is reversed, running from path 0 to path 12. Hence,during a cycle represented by a'ccmplete' revolution of the rum in itspath, the successively active rifiles will first traverse this band frompaths 1) to. c and then progressively return to path I). to beginthesucceeding cycle.

While the rifiles of the opposite side face of the outer convolution arestaggered with respect to the face described, the spacing is suchthat.the displaced relationship is not suflicient to. mate rially change theconditions as between the two faces so that it may be considered thatthe rifiies of the opposite faces of the convolution are travelingpractically in the-paths of theliinrnediate adjacent riffle of the otherface.

Figure 14 shows the presence of two of such bands, one at the larger endand the otherat the smaller end of the drum. As is apparent, each of theconvolutions of the scroll will present conditions similar to the abovewith itssidefaces providing a band individual to itself, due to th'efact that the drum wall is 'tapered from the larger to the smaller end;and while the height'of the apex of each of the convolutions is shown asdecreasing in Figure 1, the rate of decrease: is less than thatprovidedbysuch taper; butzthe individual bands will .bedisplaced-althoughtbiit slightlyfrom the; band: 11,. t c ;1 for:instance; the inner path b'for, thezsecon'd :convolutioniis-i'dis placedslightly in the direction of band a with the band width includingportions in which the paths are within the band zone shown, eachconvolution adding this condition until the band zone shown as b, c, isreached so that, in effect, practically the entire radial distance frompath b to path contains a larger number of paths approaching the numberof riiiles within the drum-with the paths as individuals, and with eachthus presenting its characteristic of individual peripheral speedconditions represented by the length of the lines within the quadrant.As a result, a revolution of the drum presents the conditions of a largenumber of peripheral speed rates active concurrently but only as havingpotential value during such rotation within the revolution, actual valuedepending upon the presence of ore material within a riflie.

If the speed of revolution of the drum in its orbit were constant, thelines of Figure 14 could be deemed to present the centrifugal forcevalues which would be developed by such revolution. However, aspresently pointed out, the system provides for such revolution of thedrum at varied speeds, thus affecting the centrifugal force valuespresent at any time, such variations, however, not disturbing theshowing of Figure 14, since the band conditions shown in the figure aresuch as to be present at all speeds of revolution, the figure presentingthe action of the drum structure and its mounting which does not changedurin the operation.

From the above, it will be understood that the drum, its mounting andthe particular type of scroll rifile carried thereby, provide aconstruction which permits of developing one of the components of thecentrifugal force values which form one of the fundamentals of thepresent invention, this being the length of the radius which producesthe respective travel paths of the individual riffles. As will beunderstood, a vast number of radii are provided in the length of thedrum, a band b-c simply indicating a few of the radii found on one sideface of the convolution, each convolution providing a bandcharacteristic of similar type, with the result that the number of radiipresent is almost infinite. There may be duplications of radii otherthan that provided by the pair found in each convolution, but theremaining duplications are in other convolutions, thus being displacedlengthwise of the drum.

Another component required in determining the centrifugal force valuesis that of the speed of rotation of the drum, and a description of thedrive for the drum is now presented, reference being had moreparticularly to Figure 4 of the drawings.

29 indicates a pair of supporting standards in spaced apart relation andlocated adjacent the smaller end of the drum, as indicated in Figure 1.These standards carry a plurality of shafts, one of which, drum shaft30, is located in the top zone of the standards and is tubular andmounted in suitable bearings 3|.

32 is a drive shaft, being located at an intermediate position in thevertical length of the standards, and is driven at reduced speed from amotor M carried on the supporting structure 26. An adjustable drivepulley 33 is carried by the shaft and is adapted to have a belt driveconnection 35 with a driven pulley 34 carried by shaft 30.

This drive relation between shafts 32 and 36 is such that provision ismade for varying the 10 speed relationship between'the two shafts, thearrangement being such that, through cam control, the constant speed ofthe drive shaft will be translated into drum shaft speeds rangingbetween a maximum and a minimum speed,

in which the speed progressively varies uniformly between these speeds.For. instance, with shaft 30 rotating at maximum speed, its speedprogressively decreases until the minimum speed is reached, whereuponthe variations, in speedincrease direction, follow until the maximumspeed is reached, whereupon the cycle is continually duplicated, thusproviding for the movement of the drum about its axis of revolution, itbeing understood that the axis of shaft 30 corresponds to such axis ofrevolution a.

To produce this action, pulley 33 is of particular type, its oppositesides being individual with side 33a secured to and rotating with shaft32. The opposite side 3312 is loose relative to shaft 32. The innerfaces of said sides are somewhat conical with the conical faces opposingeach other, belt 35 being mounted between said conical faces. Side 33bhas a flange which contacts with a control member 36 also loose on shaft32, but which is held from rotation by a member 3'! carried by a framemember 38, member 37 engaging within a recess in the periphery of thecontrol member 36. 39 indicates a spring which surrounds shaft 33 withina recess of the fixed side and which extends through an opening in theloose side 33?) and into contact with a face of the control membenthespring placing control member 36 under pressure to move the membertoward the right in Figure 4; while the spring 39 has no direct effectupon the loose side 33b, the latter will move with control member 36,due to the operation of the structure now to be described.

Drive belt 35 is of a length such as to be substantially taut when inthe position shown in Figure 4. However, one of the flights of the drivebelt is provided with an idler 40, the mounting of which is such as toinclude a spring 4| (Figure 3), so that the idler is being constantlyactuated by the spring to draw upon the flight, thus serving thefunctions of a belt tightener. Such belt tightener is thereforeconstantly urging the portion of the belt 35 traversing the pulley 33 tomove inward between the opposing conical faces of the sides 33a and 33b.Hence, if control member 36 is moved toward the right in Figure 4 byspring 39, spring 4! of the idler becomes active to enlarge this flightof belt 35 and draw the belt inward over the opposed conical faces, thuscausing the loose side 33?) to trail the movements of control member 36in this direction.

Control member 36 is movable relative to member 37 during all shiftingmovements of the member, member 36 thus being held against rotationalthough capable of being shifted in the direction of length of the axisof the drive shaft 32. While movement of member 36 toward the right isprovided by spring 39, such movement is controlled by a cam 42,operative to permit such movements of control member 36 toward the rightin Figure 4 and also to return member 36 to the position shown in suchFigure 4, member 36 being provided with a pair of adjustable pins 36aand 36b of unequal length and oppositely positioned, these pins beingadapted to operate properly in connection with the cam face of cam 42.As shown in Figure 4, the long pin 3 6a is contacting the high pointof'the cam which thus retains member 36 in the p-osition'shown. As thecam rotates, the receding camface permits control member 36 to movetoward the right, under the action of spring 39, with pin 36c remainingin contact with the face, this continuing until the low point of the camreaches such pin, at which time the high point of the cam contacts withthe short pin 36b to prevent further movement of. member 35 toward theright. As the cam continues its rotation, the face of the cam activewith the pin 35a applies pressure on pin 35a to move control member 35in the opposite direction, this continuing until the high point of thecam reaches the positionshown in Figure 4. Duringthis return movement ofcontrol member 35, it becomes active on the loose side 33b to move suchside insimilar direction, thus applying pressure upon the edge of thebelt 35 in opposition to the power of spring 4!, to thereby cause thebelt to move toward and into the position of Figure 4.

Through this arrangement, the drum revolution will be at speed ratescontrolled by the position of belt 35 within the adjustable. pulley 33with the maximum speed provided when the belt is in the position shownin Figure 4, and with the minimum speed provided when belt 35 has movedinward between the sides 33a and 33b to its inward position as permittedby the operation of cam 42, the low speed being at the time when thehigh point of the cam face is cooperating with pin 3%; while thedimensions shown in Figure 4 are more or less illustrative, thearrangement shown would set up approximately conditions in which tworevolutions of the drive shaft would provide substantially onerevolution of the drum, when belt 35 is in the position shown in theview, and require four revolutions of the drive shaft to provide arevolution of the drum when belt 35 is in its inner position, cam 42controlling the speed rates between these maximum and minimum speeds.

43 indicates a control shaft mounted in bearings on the standards 29 andlocated below drive shaft 32, the shaft 43 is driven from the driveshaft through a drive belt and pulley structural units indicated broadlyas 44 and in which the pulleys are secured to the'respective shafts, sothat shaft 43 is in definite drive and speed relation to the driveshaft. At one end of shaft43 is mounted an adjustable pulley 45 of thetype of pulley 33, having a fixed side 45a and a loose side 45b with theopposing faces of these sides formed conical. Since the fixed siderotates with shaft 43, the structure serves as a drive formationcooperative with a belt 45 which also trains over a pulley 4'! which iscarried by the tubular shaft 420. of cam 42. Shaft 42a is rotatablefreely on drive shaft 32, but is held from endwise movement thereon.Hence, when pulley 4! is rotated by adjustable pulley 45, the cam 42will be rotated at the speed determined by the relation between thedimensions of pulley 4'l'and the dimensions which may be active withrespect to pulley 45. Drive belt 46 is equipped with belt tightenersimilar to idler 45, thus placing belt 46 under continuous tension.Hence, if the loose side 45b is moved away from the fixed side 45a ofpulley 45, belt 46 will move inward on'the pulley to thereby decreasethe effective diameter of pulley 45; or, if the belt is in an innerposition and the loose side 45b is moved toward the fixed side 45a, thebelt will be moved outward, thus increasing the activ diameter of.thepulley. The.

action is somewhat similar tothat described in" connection with pulley33, with the exception that the position of the loose side 45b iscontrolled by manually adjustable means, and the position of the sideremains constant until a new.adjustment is had.

Any suitable control means in this respect may be employed, that shownbein in the form of alever 49 having one end secured to the frame.member 38 and its opposite end cooperatingwith an adjusting device 50mounted on the structure 25, lever 49 carrying a projection 49a whichco-- operates with the loose side 45b. When the lever 49 is moved towardthe leftin Figure 4, side 45b is moved away from side 45a, by the belttightener 48 which causes belt 46 to move inward on pulley. 45. If thelever is moved in the opposite direction, it forces the loose side 4511toward side45a... and thus shifts the belt 48 outwardly on the pulley.

From the above, it will be understood thatxthe drive shaft 32 and thecontrol shaft 63 rotate at constant speeds; cam 42 rotates at manually"adjustable speeds, but when adjustment has been had, the rotation is atconstant speed. On the other hand, drum shaft 30 rotates at variablespeeds, this being due to the fact that the drive. from shaft 32 isthrough the adjustable pulley. 33, which, through the action of the cam42, causes the drive ratio between pulley 34 and. pulley 33 to varybetween maximum and. mini-v mum speed conditions; for the purpose of thepresent description, the respective ratios in these extremes, asindicated in Figure 4, are .tWo rev-' clutions of the drive shaft foronerevolutionofr. the drum shaft (2:1) in the maximumspeed ex.- treme,and four revolutions of the drive shaft to; one revolution of the drumshaft (4:1) inthe. extreme minimum position; since. the cam42. is: ofconstant fixed dimensions, it willb'e under;- stood that these ratiosare constant in service; regardless of the speed changes which may beprovided through the manual adjustment of pulley 45.

For the purpose of explanation, it is; assumedthat the extreme maximumspeed ratio as be:- tween pulleys 41 andq45 is 26:15 (15 revolutions ofpulley 4! to 26 revolutions of pulley 45) while in the extreme minimumposition of belt 46, the ratios will be 26:8 (26'revolutions of pulley45 tov 8 revolutions of pulley 41). To obtain a glimpse.

of the possibilities as to speeds, etc., the following. explanation ismade, based upon the above data:

Assuming that the manual adjustment has placed belt 43 in its maximumspeed position, one revolution of the cam will be provided by 1.733revolutions of control shaft 43, with the latter provided by 2.817revolutions of the drive shaft 32, the latter being driven from the.motor M. When the manual adjustment is at its ex-- treme minimum speedvalue, control shaft 43 has 3.25 revolutions for one revolutionof'the'cam, while drive shaft 32 will have 5.281 revolutions. Since thedrum shaft is rotated from drive shaft 32, it is possible to approximatethe extremes. of' the speed limits of the drum shaft from theabove da a.

For instance, in the position of 'belt'35 shown in Figure 4theextreme-maximum speeds-thedrum shaft would rotate 1.408 revolutionswhile the cam 52 is making one revolution; when belt.

35 is in its extreme inner limit, the drum shaft will rotate .704revolution during one revolution. of the cam 42. When belt 46 is in.its'extreme minimum speed position, the drum shaft'will rotate'2,645revolutions to one revolution of the cam 42 when belt 35 is in theextreme maximum speed position, and will rotate 1.322 revolutions in theextreme minimum speed position.

As will be-understood, the action of the cam 42 constantly varies thespeed. ratios between pulleys 34 and 33, so that as the cam rotates, thespeed ratio between the pulleys progressesfirst in one direction andthen in the other direction-between the 2:1 ratio and the 4:1 ratio,thus providing for an infinite number of ratio values between these twovalues, in which the ratio 3:1 is an intermediate value, thesevariations being constant in direction and progression fromone extremeto the other and then through a return in which the ratio progression isreversed, the result being that there is a zone in each extreme in whichthere is an approach and a recession in which the rate of progression isequal on opposite sides of the actual point at which the progressionshifts from one direction to the other; on of these points is provided.by the high point of cam 42 and the other by the low point of such cam.

As is-apparent, the drum shaft values given in the above tabulation donot give the actual distance of advance of the drum, representing simplyvaluesprovided in the extreme positions of belt 35j since cam 42 has asymmetrical active face, it'is possible to approximate th actualdistance of the-drum advance by averaging the values indicated. Forinstance, with pulley 55 adjusted to provide for maximum speed, thedrive shaft 32 will have 2817- revolutions to produce one revolution ofcam 42, and at the same time would produce a drum advance through adistance corresponding to 1.05 revolutions; similarly with pulley 45adjusted to the minimum speed conditions, the drive shaft 32 would have5.281 revolutions to produce one revolution of the cam 42, and at thesame time provide an advance of the drum through a distance equivalentto 1.984 revolutions of the drum. These distinctions provide a number offactors which are of value in understanding the operation of theapparatus.

To illustrate one of these factors, the specific rifiie which is on thenadir point of the drum revolution at the instant cam 42 is at its highpoint with the cam rotating under maximum speed conditions it will beapparent that the riiiie will advance through the quadrant with adecreasing progression as to speed, although the rifile itself istraversing a path concentric with the axis of revolution; when thisrifile again reaches such nadir point during the revolution, cam 42 willnot have completed its revolution, so that the rifile will advance 18degrees beyond such nadir point before the cam high point reaches itshigh point conditionduring this 18 degree angular distance, the rifiiewill advance under increasing progression conditions and then pass tothe decreasing progression for the remainder of the travel in thequadrant; on the next appearance of the rifiie at the nadir point,similar conditions will be present, but the rifiie would travel througha distance of 36 degrees before the change occurs, the succeedingappearance providing the change after an advance of '72 degrees, withthe next appearance providing an advance to the 90 degree point whichmarks the end of the quadrant. In other words, under the conditionsnoted, the direction of speed progression development will have beencompletely 'reversedat the end of five revolutions of the drum from thecondition of a decreasing progression to that of an increasingprogression, this effect being produced through the fact that the drumrotates a distance of 18 degrees in addition to a revolution while thecam is makin a single'revolution. This shift in the position of theriflie during successive revolutions will, of course, continuethroughout the complete revolution of the drum, so that the particularconditions just described would be repeated after the drum has madetwenty revolutions, thus providing a cyclar condition of twentyrevolutions which would be the operating standard under theseconditions.

It will be understood, of course, that during this progressive advanceof the changing points of the direction of speed p ression. th r fiiewill have passed through the low point of activity of the cam, so thatthe changing point, for the cam low point position will also advance;hence, there will be, at the proper time, a similar group of fiverevolution effects developed within the quadrant with respect to theriffle in question, but in this group the action will be the reverse ofthat pointed out, in that the decreasing progression will become theincreasing progression and vice versa; between the activities of thesegroups, the direction of progression would remain constant, but madeunder conditions that are exemplified by the progressive advance of thechanging point through the quadrant above pointed out. In other words,while the riiile may make successive appearances, each of theappearances is under different speed conditions, it being understoodthat the 18 degree advance of the changing point with each revolutionmeans that the rifile will have its succeeding appearance at the nadirpoint under either higher or lower speed conditions than the previousappearance.

Similar conditions will be present when pulley 45 is operating underminimum speed adjustment, excepting that the values and the effects ofthese will be changed.

For instance, at this adjusted speed, one revolution of the cam takesplace while the drum is advancing 1.984 revolutions, this number beingslightly less than two revolutions of the drum for one of the cams.Consequently, the shifting points as to a selected riiiie will graduallyadvance in the reverse direction from that indicated in the aboveanalysis, and at an exceedingly slow rate, the general cyclardevelopment covering approximately 240 revolutions before actualrepetition. This reversal means that the change in progression wouldcome just before the rifiie again reaches the nadir point, thesuccessive changes in this respect representing the high and low pointsof the cam travel.

In other words, under the maximum speed conditions referred to, thetravel between the high and low point positions of the cam will takeplace during the drum advance through a little more than half of a drumrevolution, while un-.

der the minimum adjusted speed conditions the drum advance between suchhigh and low points will beslightly less than a complete revolution,this distinction representing the variations which provide the range ofadjustment so far as the illustrative dimensions of Figure 4 areconcerned. For instance, if the adjusted speed provides a ratio of 26 to13, the drum advance for one revolution of the cam 42 would be 1.219instead of the 1.05 above referred to. Or if the adjusted speed providesa ratio of 26 to 10, the drum ad- Vance during the period of onerevolution of 125' the cam 42 "-would'lbe 1158.4 as :compared .to the1.05 :value. analyzed :above.

The specific :analysis thus made pertains to a particularrifileof thefirst scroll convolution at the largereend .of the drum. .The travel ofthe riflie .provides a speed regimen of .a particular type .during arevolution ..of the drum. However, only .the quadrant of the drumcircumference, ilustrated in Figure 14, .is active .under serviceconditions,1the remaining portions of the travel through the path ibeingentirely/inactive or, as presently explained, engaged in-preparing forthe activities within the quadrant.

1This-regimen applies individually to the remaining rifiies carried bythis convolution, each riffle having its individual travel :path aspreviously explained. All :ofthese rifiies have the time length of thisquadrant activity similar. There is, however, -a.distinction present asbetween the several rifiles of. a convolution, in that the'radii ofdifierent rifiles difier in length, as explained above,..due to theeccentric mounting .of the drum. .T-his difference-in radius length doesnot affect 'ithe :regirnen characteristics of the .riifle excepting such.as are brought about by :this changein the length ,of the radius. Forinstance, as shown in Figure .14, the arcuate travel of therifile-tr-avelingon line .0 is similar to that traveling .4 on ;line'band both have the same time length within ,the quadrant; .but thespeed.of the regimen withrespect to theriflie traversing line b will :be less"than-that of the riflie traversing line 0,;due to the difference in thelengthof the arcs-forming these paths through .the quadrant.

The same distinction ,is present between the riflles of the convolution,so that the speed regimen ,ofeven adjacent riiiles-on the same face ofthe convolutionwill not be exactly the samethe difierence is veryslight, but such difierence is necessarily present, due to the variationin the lengthof the radius of such rifiies. The same conditions will bepresent in connection with the succeeding scroll convolution, the rifiiewhich is in the nadir position when the cam is at its high point, withthe exception that the rifiie of the second convolution is of slightlyless radius length than that of the rifile of the first convolution, theradius of the riiiles decreasing in length in successive convolutions,thus affecting the actual speed conditions but without disturbing thespeed regimen.

Asa result, there is provided withinthe scroll, a, great number ofindividual ri'liles, each of which travels its individual path and underconditions which provide for practically individual speeds based.'onaispeed'regimen that is common to all of them. Difierencesmay beexceedingly'small even minuteas between rifiles, but they are present.The feature in' this respect is of importancewhen considering theeffects set up by the revolutions of the drum-the centrifugal forcevalues which are developed through the movement of the drum during itsrevolutiomthe various differences as to speed and of radius lengthsetting'up corresponding differences in the centrifugal-force values,due to the variations in speedand in length of the radius of theindividual rifiles.

The reason for the presence of this infinity of centrifugal 'forcevalues can be understood from the fact that thematerial being subjectedto the action of theapparatus is of atype in whichtheorecontent is inthe form of very small .particles and hence of low weight factor type.:Since thetore contentof the pulpcontains 16' particles :differing as.to weight characteristic, lf the. drum is :to provide for classifyingand separating activities, .it must-be necessary to distinguish betweenparticles-even though the differences in weight value and othercharacteristics are minute. The detection of these differences isprovided more particularly by the use of the centrifugal forcecharacteristic, so that fit isessential that the centrifugal forcevalues be of ractically an infinite number :of values difiering fromeach other, with the differences in value of the minutest type.

Another import-ant characteristic in the operation of the apparatus isthe character of the riflie per se. Some of the riflie'char-acteristicshave beenpointed out above, in that :they:sex tend from the median lineof theconvolution and extend over the inclined face of .a'sidewof theconvolution toward but spaced from the line which marks the divisionbetween adjacent convolutions; this arrangement-is shown moreparticularly in Figure 9 and insectioninFigures-ll) and 11, whichprovide structural characteristics of the riffle. An important featureof these characteristics is the fact'th-at the direction vof length ofthe groove which provides the riffle extends at an angle ofapproximately 45-,degrees to the path of travel of the inner end ;of therifiies, with the angularity causing the length of the rifile to have atrailing aspect with respect to the movement of theinnerend of theriflle; this is indicated by the arrow X in Figure .9, the arrowindicating a-direction of travel of tthe ccnvolutions during drumadvance. 'In addition, the groove which produces the'rifile is of vshape (Figure 11) with-the bottomof the groove;extending at an angle tothe base but of less-angularity than the angularity ofthe side :of .theconvolution (Figure 16).

These characteristics provide a definite and important function in theoperation of the apparatus. For instance, when the inner'end of theriiile reaches the nadir position of its path of travelgthe remainder ofthe riflie-being of trailin" characte1'istic-will be extending inadirection aw y from-thequadranuinto which thisposition or, theriiile'forms the entrance; hence, the van point .end of the rifliewill'not reach such nadir positionuntilthedrum has advanced a smalldistance. In thisposition, the vanishing point end of thegroovewouldtendto be slightly raised with respect vto-its position at the nadirpoint, so that the';bottom of the glOOVGiWOlllli have a slightlydifferent relation to the :path of Y travelof this: endof :theriflie-than it would-;-have at the-point wherethis end is in the nadirposition of its travelipath; whenthe latter-position is reached, theinner endof the riflie willibe advanced a-,certain-;distance and hence@will have 1 caused such ginnerendzto be slightly raised :relativetoaghorizontalplane through;the-nadir point, thus changingtheangularityof-the'bottom of thegroove. Asthe rifileadvancesthe angularitycharacteristics of the groove bottom relative to a horizontal plane-thusproduced Wi'H-r'be generin the regimen speeds at the opposite ends ofthe groove 23a; the inclined bottom 231) thus provides for an increasinglength of radii in the direction of length of the groove, with theresult that the bottom of the groove itself will provide for increasingcentrifugal force values in the direction of the disappearing end of thegroove. In other words, the centrifugal force value on a particle withinthe groove will increase as the particle traverses the groove from itsinner to its vanishing end.

Another feature in connection with the riffle operation is provided bythe specific location of a particular rifile within its travel paths ata particular moment, and brings into the conditions the weight of theparticle itself, For instance, a particle within a groove will have itscomplete weight added to the centrifugal force value when the trailingor disappearing end of the groove passes the nadir point, since thedirection of length of the groove is then wholly down- Ward. On thecontrary, any particle present in a groove located on the opposite sideof a vertical plane through the axis of revolution, would tend to haveits weight opposing the centrifugal force value, because the length ofthe groove is then extending in an upward direction, excepting in a zonein the vicinity of the nadir point, due to the trailing characteristicof the outer disappearing end of the groove. Within the nadir pointzone, there is a gradual change in these conditions since the groove isthen traversing a zone in which the entrance is with the trailing end ofthe groove uppermost, While the trailing end becomes lowermost as thegroove leaves the zone.

This feature is of service, due to the fact that the ore pulp isdelivered to the side of the drum which is on the opposite side of avertical plane through the axis of revolution from that on which thequadrant is located, so that the trailing ends of the groove extendupwardly at such time and tend to cause any content reaching thetrailing end to move downwardly within the groove toward the inner endof the groove, a condition which is a part of the preparation period forsubjecting the content to the action of the riiiies within the quadrantzone. While the specific centrifugal force action present at theparticular point where the ore pulp is being supplied to a groove ispresent at such time, in this location the weight of such content is inmore or less opposition to the centrifugal force value, so that thecontent will readily flow toward such inner end and remain at such endas the groove continues its approach toward the nadir point, thegradually changing conditions through the nadir point zone tending toarrange the content for proper action within the quadrant zone.

On the other hand, a particle carried by a riiiie entering the quadrantzone under decreasing speed progression conditions, may be subject toother action than the rejection condition pointed out above. Under theseconditions, the particle weight-which remains substantially constant mayserve a diiferent purpose than that in connection with the rejectionconditions. While the weight of the particle remains constant, thecentrifugal force value which tends to hold the particle within thegroove or cause it to be discharged lengthwise of the groove, becomesprogressively less as the rifile advances, thus decreasing thedifierence in value between the force walue and the weight of theparticle. If this difference is reduced to zero or becomes a growingdifference in favor of the Weight factor, the

weight will becomes dominant; and if this takes place at a point withinthe quadrant where the riflle has reached one of the upper positionsshown in Figure 15, the particle weight willcause the particle to moveacross the side face of the rifile instead of lengthwise thereof, thusplacing the particle in position where it can readily enter a. rifiiecarried by a different face of the same convolution, thus, in fact,serving to advance the particle in the direction of the smaller end ofthe drum.

In practice it has been found that these two conditions, one of whichinvolves the movement of a particle lengthwise of the groove and theother in which the particle is moved across the length of the inner endzone of the groove, become of great importance in that they produceconditions that are active in classifying and separating the differentparticles. In such practice the ability to advance the particle or to berejected through this procedure, provides a regimen characteristic suchthat it has been found that particles will be rejected under high speedconditions and will advance under low speed conditions with theadvancing particles being those which it is desired to separate from themass of particles carried by the pulp. The infinity of centrifugal forcevalues present at any particular speed adjustment will enable theapparatus to inherently provide the conditions which will permit of adifferent movement of the particle-to move the particle transverselyover the side of the groove instead of lengthwise of the grooveand thusprovide the desired selectivity, since particles which do not passacross the groove face in this manner are rejected and passed lengthwiseof the groove.

As will be understood, these conditions can be made to apply toparticles of different specific gravities through the manual adjustmentof the speed. Where the speed rate is decreased, the centrifugal forcevalues of the entire range of centrifugal force values is shifted to alower speed value range and thus decrease the effect of the centrifugalforce on the particle which may be carried by a particular rifiie sothat a particle of less specific gravity will reach this zone in whichthe selection as to travel path of the particle is made, while if theadjusted speed is increased, the selection can be made with respect toparticles of higher specific gravity.

The front end zone of the drum is provided with an annular casing 5 I,in which the front wall Ella is spaced from the front large end of thedrum and extends inwardly a radial distance such as to provide a centralopening to the casing, the radial length of the wall 5 la being suchthat'the margin of the opening lies some distance inside of the diameterof the drum at its larger end, so that the casing tends to cover theriffie zone at such end of the drum. The opposite wall 5|?) of thecasing overlies the drum in advance of the track 23, the two walls thusforming a receptacle below the open end of the drum to receive treatedpulp material passed through the open end of the drum. The casing issupported on suitable legs 52 carried by the supporting structure 26,the casing being non-rotatable with the drum; the bottom wall 5E0 of thecasing and which forms the bottom of such receptacle, is formed with adischarge opening providing an entrance to a discharge conduit 53, thusproviding for practically immediate removal of the material which passesfrom this end of the drum. As shown in V which may be delivered 19Figure 2, the casing opening thus exposes the central zone of theinterior of the drum.

As indicated in Figure 2, the front face of wall m carries an elongatedstrap-like member 54 which is secured to such wall and hasan'intermediate portion overlying a zone of the casing opening. Member"54 is designed to carry the structure for introducing the pump materialinto the drum. For convenience in showing the character of suchstructure, the latter, with member 45, is shown in Figure 1 as displacedfrom its actual position in order that it may be included within thesection of that figure; Figure 2 shows the actual location relative tothe axis of the drum.

The delivery structure is in the form of a tubular member 55 of desiredlength, closed at its outer end and having its inner 'end formed withopenings 55a through the wall of the member and having a guard 55bbeyond such openings, the structure at this point being such'that pulpmaterial can flow lengthwise of member 55 to its inner end zone where itis free to pass out through the openings 55a, the guard 55b forming awall which prevents the material from being jetted forward of a desiredposition, the openings 55a permitting discharge laterally. The outer.end of the member is provided with an elongated opening 550 having aguarding flange 55d, the 'flange and opening forming the entrance to theinterior of member 55, the opening flange 55d having dimensions topermit the ready entrance therein of a supply pipe 56 leading from thesource of supply of the pulp, not shown. The member 55 is mounted in abearing 57 carried by member 54, the bearing being internally threaded,member 55 being complementally threaded externally for a suitabledistance, the purpose being to permit adjustment of the position ofopenings 55a relative to the length of the drum. Member 55 has its outerend provided with a wheel 58 by which the member 55 can be rotated so asto provide for such adjustment, it'being understood, of course, thatpipe 56 is removed during the period of adjustment and that the close ofthe adjustment leaves the guard 55b as extending upward to permit there-introduction of pipe 56. This adjustment of the position of member 55is provided to compensate for differences in the size of the particlecontent produced by the grinding of the ore material, the member 55being moved in the direction of the smaller end of the drum as thefineness of the content is increased, and moved toward the larger end ofthe drum with the content ground to a coarser mesh status. 7

As indicated in Figure 2, the location of member 55 is such that thematerial passing through openings 55a will fall upon the rifile zonewhich is vertically alined with such openings, the material thus passingdownward onto the rilfle zone materially in advance of the nadir pointof the drum. At such time, the trailing portions of the riffles areprojecting upwardly, so that material reaching such trailing parts willtend to flow toward the inner ends of the riflie, the material fallingin the zone between opposing rifiles of adjacent convolutions, tendingto move into such trailing portions and thus move toward the inner endsof the riiiies. Hence, the arrangement is such 'as to deliver the majorportion of the pulp at such inner ends of the riflles as the latterapproach the nadir point to begin entrance into the quadrant heretoforereferred to. The amount of pulp p r unit of. t m Qicourse, determined bythe dimensions of opening '55a,'but it will' be understood that whilethe supply is continuous, the amount which is being delivered per unitof time is su'fliciently small as to prevent overloading of the riflles,it being understood that the continued movement of the drum causes aconstant change in the riffles which are receiving the pulp in thismanner; in this "connection, the amount of the content of a rifile willprobably not be uniform, due to the fact that constantly changing speedconditions are present in the movement of the drum, so that there may bea slight decrease in the amount of a rifile during periods when the drumis rotating at its higher speeds, since a rifile then passes out of thesupply zone more rapidly; the difference, however, is small as betweensuch high speed .and low speed conditions, the openings 55abeingdesigned to permit feed of the material without overloading theri'illes during the slow speed conditions.

When the falling pulp comes into contact with the .drum, the radius andspeed factors that are provided by the drum rotation immediately .becomeactive to set up the centrifugal force effects which the apparatus isdesigned to produce. Since member 55 is located at a distance precedingthe arrival of a riffie at the nadir point, it will be understood thatthe pulp content which may be contained within a riffle so supplied willbe subjected to centrifugal force activity prior to the arrival of theri'fiie at such nadir point.

For instance, assume that the pulp material is being supplied to theriflle which reaches the nadir point simultaneously as cam 42 reachesits high point. In such case, the r-iflie will approach the nadir pointunder conditions of an increasing progression so that the centrifugalforce values will be approaching those present at the instant of changein progression provided by the cam, these values being indicated by theline 0 in Figure 14 of the particular band which presents the activitiesof the rifiles of the particular convolution to which thepulp is beingdelivered. During this approach, it is apparent that not only will thepulp material tend to move in the direction of the inner end of therimedue to the upward inclination of the trailing portion of the groovebut will, at the same time, subject the pulp content to the effects setup by these increasing centrifugal force values.

Since the pulp is made up of the comminuted ground material, and thewater added to produce the pulp characteristic, it will be understoodthat the content of the riflie will be made up of particles of variousspecific gravity values as well as fine dust particles, etc.these lattertending to produce the slimes effect that is present. Hence, it can beunderstood that there will be a tendency of the heavier particles tomove downward in the mass, due to the increased centrifugal force valuethat is produced by the increased weight of the particle. I-I'ence, asthe rifile is advancing, the tendency is for these particles to :movetoward the bottom of the riflie, so that as the riflle reaches the nadirpoint, there will have been a tendency to stratify the various membersof the pulp contained within the rifile. This stratification trend isnot completed during the approach but is completed during the movementor travel through the quadrant, under conditions presently explained.

On the other hand, should the riifle receiving the pulp content be onewhich reaches the nadir zone as cam 42 reaches its .low point, theapproach of the rifile to the nadir point will be under conditions of adecreasing speed progression, under which the centrifugal force valueswill be decreasing so that the riffle is reaching the nadir point underminimum centrifugal force values and the travel through the quadrant ison the basis of an increasing progression. Under such conditions, thestratification trend referred to would be less pronounced in such actionand would be enhanced through the fact that the travel through thequadrant is under increasing centrifugal force values. Referring toFigure 14, the conditions would approximate those represented by line bof the band which represents this particular convolution.

Obviously, intermediate rifiles will pass through such preparation zoneunder the particular conditions that are provided by the location of therifile between these extremes, the character of which will be understoodfrom the previous description.

As heretofore pointed out, the trailing portion of the rifiles extendsupwardly at the point where the pulp is delivered to the riffles, sothat while the pulp content becomes subject to the centrifugal forcevalue of a rifile, the force is exerted in a direction practicallytransverse to the direction of gravitation, so that the pulp contentwill tend to gravitate toward the inner end of the groove as the drumadvances the rifile during the approach of the riffle to the nadir pointposition; hence, the tendency to set up stratification initially isthrough the combined action of centrifugal force and gravitation, theangularity of these forces relative to each other being graduallyreduced as the rifile advances until, at the nadir point, the two forcescoincide in direction, thus tending to aid in producing thestratification trend within the pulp content during this period. Inaddition, the trailing portion of the groove and its relation to theinner end of the groove becomes changed during this period since therifiie is then approaching the nadir point so that the bottom of thegroove will gradually reach a horizontal status and then graduallydevelop the inclined effect shown, for instance in Figure 10, with thetrailing end below the inner end of the groove, this development beingfollowed by the gradual change in inclination of the bottom of thegroove produced as the riffle passes into the quadrant zone with itsinherent upward rise of the inner end of the groove in following thecurvature of the are provided by the quadrant. In this latter stage,gravitation cooperates with the centrifugal force, but the coincidentalcondition present at the nadir point is changed to a graduallyincreasing variation in the two forces, with a material distinctionbetween the conditions on the opposite sides of a vertical plane throughthe nadir point, due to the fact that within the quadrant zone thedirection of length of a groove extend downwardly with the inclinationvalue increasing as the rlfile advances through the quadrant.

Due to these conditions, the stratification trend which began in theapproach zone to the nadir point is continued as the riiile proceeds,with the rapidity of development of the stratificaticn trend dependingupon the particular speed conditions which may be present during thetravel of the rifile through the quadrant. If the riffle reaches thenadir point concurrently with the high point activity of cam t2, thecentrifugal force values within the quadrant will gradually decrease andthus tend to slow the stratifying trend action; on the other hand, ifthe rifiie reaches the nadir point concurrently with the low point ofcam 42, the travel of the riffle through the quadrant will be under anincreasing progression of centrifugal force values and thus tending toincrease the stratification trend action, in which case there will be agreater tendency for the heavier particles to reach the bottom of thegroove and become subject to the increasing centrifgual force valueswhich are produced by the downward inclination of the length of thegroove, so that such particles would inherently tend to travel towardthe trailing end and thus lengthwise of the groove, and as a result, setup the particle rejection action previously pointed out, the rejectedmatter moving out of the riiile and into the intermediate space betweenconvolutions, which space is comparatively smooth in surface, so thatsuch rejected content can move downwardly within this space toward thebottom of the drum. It is possible that the heavier particles would bedischarged from the riflle at such speeds as to tend to throw them intoriffles of the adjacent convolution, or even over the apex of suchadjacent convolution, the movement being in the direction of the largerend of the drum; in such case, the rejected particles would be takenaway from the convolution which is forming the initial zone of action,and be subject to the conditions set up by the adjacent convolution.

Since the eccentric mounting of the drum sets up differences in radiallength as between adjacent riflies or rifile zones-the difference beingleast in adjacent riiiies and reatest between the zenith and nadirrifiles when the drum axis is vertically alined with the axis ofrevolutionit will be understood that the action as between two rifiiesmust necessarily differ as to timing. In other words, adjacent riflieswill reach the nadir zone at slightly different positions of cam 42, sothat the high point of the cam which is used as one of the illustrativecontrols in the above description would be active on one riffle and thencontinue its advance, so that the succeeding rifile would reach thenadir point after the high point of the cam has passed its highestposition, this difference being progressively developed as riiilef011OWs riifle in reaching the nadir point, and reaching its maximumwhen the riffle opposite the first named rifile at the time the latterreaches the nadir point, itself reaches the nadir point, the differencesbetween these two riflies representing the effects set up through theeccentricity of the drum. As the drum movement continues, theprogression thus indicated is reversed. As a result, the action withinthe quadrant zone inherently differs with each of the riflies of eachhalf of the drum.

The Stratification trend referred to is not a true and completestratification, as will be understood from the fact that while the crosssection at the inner end of a riflie is small with respect to theapparatus or even to portions of the apparatus, yet the cross section islarge with respect to the particles contained within the pulp, so thatthe content of such inner end generally includes a number of suchparticles, these being made up of the ground material and which includesmetallic as well as stone material and p0"- sibly dirt particles. Theseparticles may differ not only as to dimension, but more particularly asto specific gravity values, although the smallness of the particlesrenders the difference in such values as being very minute. However, be-

ing solid as compared with the fiowable forrn ef the pulp, each particlehas its "individualeffeict with res ected the centrifugal force valueswhich may represent in the 'riffle. Pres'ui nably, partiel'es having thesame specific gravity :characteristics would be movable within the {pulpat substantially similar rates under the eemrirugai force effect, whileheavier particles would move through the pulp at a more rapid rate, dueto the fact that their specific gravityvalue isf greater Wlthres'pect'tothe fiowable'portion tha'n of particles of lower specific gravity.'Hence, there would tend to be particle movements which fdiffered as torate "when traveling through the pulp, this action tending to-set up thestratifying'cha'racteristics referred to, since the heavierparticleswould probably'r'each the bottom of the groove in advance of the lessweightier particles; the weightier particles may thus tend to pre-einptspace conditions within the bottom zone of the groove and "in-such casewould tend to prevent the less weighty particles from reaching thebottom, the latter being 'unable to displace the hea'vier particles.Where the heavier partieles are rejected by passing lengthwise of thegroove, the less Weightier particles are then able to advance.

While the Walls'of the groove move bodily within the circular path andthus move as a unit, sueh movements conform to the conditions based onthe length of the radii which are present within a the groove. Forinstance, the radius length at the inner edge of a side of the groove isless than the radius length at the bottom of the groove,the differencein such lengths being represented by the depth of the groove;thearcthrough 'which such inner edge advances through the quadrant willtherefore be slightly less in length than that through which the bottomof the groove passes However, since the wall of thegroove structure isunitary, this provides no appreciable effect within "the groove.

However, while a content Within the groove or riflle would present thesame conditions as to the length of radii, the fact that such content isnot only flowa'ble but is made up of particles differing in specificgravity values, may produce a slightly different effect from thatproduced with respect to the walls of the groove. Since the particlesare movable through the pulp, there may be a slight creeping efiect asto particles brought about by this diiierence in length of radii atdifferent portions of the groove. For instance, a particle which ispositioned at the mouth of the groove, when moving downward within thegroove under the centrifugal force value efiect, is actually passinginto a portion of the groove which is traveling through a slightlyincreased distance and thus at a slightly increased speed-the differenceis very minute, but by comparing two parti'cles which are brought intocontact during such movement through the pulp in the downward direction.Since the lower one of the two is traveling under the longer radiuslength, its speed would be slightly greater than that of the otherparticle traveling under less radius length condition; the difierenoe inthis respect will possibly be imperceptible, but the trend is presentand has its eiiect where the two particles have the same specificgravity values, since the slightest relative movement between the twolaterally can tend to more completely setup the conditions known as thecoefiicient of friction. ,In other words, the two particle's, bothsubject to centrifugal force conditions, may have the slight lateralmovement needed to bring about a more perfect surface concarries theconvolution rifiies in tactfof the t andih s de l 1 mato'ndition that isespecially beneficial during the concentration activities of the deviceas more particularly pointed out hereinafter.

The assembly thus far described presents a number of characteristicfeatures. Among these is the fact that each of the convolutions of thescroll 'rifiie practically forms an individual zone of operations. Forinstance, it is possible that in the rejection from a rifiie, one ormore of the particles which would notin itself have been rejected, willpass out with the pulp content. This would then pass to the bottomunless the rejection has been with a force sufficient to carry it overthe ridge of the succeeding convolution, in which case, the particlewould be active with a different convolution until it is again advanced,whereupon it would then again have its activity within the formerconvolution. V v

Since each rifiie actually traverses a circular path, the eccentricmounting of the drum sets up the condition that while each riille hassuchfcircular path ertravel, yet the values produced during the travelin the path and which combine to produce centrifugal 'force activitydiffer to a slight degree from "those of adjacent riffies. While all ofthe rifiles partake of the constant variation in speed conditionsproduced through the action of cam '52, the arrangement is such that thecentrifugal force values effective within a rilfle diifer from those ofadjacent riflles to a very slight extent, due to the eccentric mountingof the drum, the differences increasing when the rifilesbeingcornpa'red'are located more remotely from one I another within theconvolution. Hence, the zone provided by the convolution presents alarge number of centrifugal force values which become active upon thecontent of the rlfiies while passing through the quadrant,

There is no fixed regimen provided for a particle within suchconvolution zone; this is due to thefact that the question of whichriflie may be in the path of the delivered pulp is a matter of chance,and since there is this constant variatron in centrifugal force valuespresent as between rifiies, it is possible that a particle may belocated within the zone for but a short time or for a lengthy time. Itmay be noted that in extensive tests made over extended periods, it hasbeen found that each of the desired particles, at some time or other,during the operation, reaches the upper limits of the quadrant and isadvanced; this result may require extended periods, but the operation ofthe apparatus is such as to bring about this result.

The above characteristic is present with each of the convolution zones,but although the drum similar manner to that above referred to, thedifference in values, due to the fact that the convolution itself isbased upon a different diameter of the drum, thus producing thecondition that convolutions toward the smaller end of the drum havecentrifugal force values lowered, while the convolutions toward thelarger end of the drum have these values increased. The differencebetween the values of adjacent convolutions may be small so that theremay be an overlappin of centrifugal force values as between adjacentconvolutions; th s is referred to above in connection with Figure l4 inthe presence of overlapping band's. This overlapping of values isprovided for the reason that when a particle has passed from oneconvolution to another, -it becomes subject to the same general regimenconditions that are found in connection with each of the convolutionsand hence there is a need for the presence of possible duplication ofvalues. It will be understood, of course, that a rifile of oneconvolution which may be alined with a riffle of an adjacentconvolutionwill not present exactly the same centrifugal force value in bothconvolutions at the same time; the overlapping of values comes from thepresence of rifiles that are out of alinement in the direction of lengthof the drum, since the difference in diameter of the drum produces thelimiting factors so that a riffle alined differently would be requiredto produce the overlapping value relationship.

As a result, the drum convolutions present a great multiplicity ofcentrifugal force values which vary practically constantly with each ofthe riffles, due to the fact that the drum revolution in its path isbeing subjected to the changed conditions brought about through theaction of cam 42, the shape of the latter producing a constant change inthe conditions relative to belt 35 and hence a change in the speed ofmovement of the drum about the axis of revolution. These variations,except as to the minute specific differences in centrifugal values, arecommon with each of the convolution zones and the rifiles of each zone,the result being that the particle content of the pulp becomes subjectto many testing operations with respect to centrifugal force valuesdiffering one from another, tests which may take a short or a longperiod of time, but, in the end, the particle of desired value willreach a rifile of the zone which will serve to advance it to thesucceeding zone; many rejections may take place during the tests, but,in the end, the tests with respect to such zone come to an end by thefact that the particle reaches the point where it is favorably locatedto advance into the succeeding zone.

In addition to the provisions for creating the centrifugal force valuesabove explained, the apparatus includes controllable means for admittingwater to the interior of the drum while the latter is in operation. Aswill be understood, the pulp originally introduced contains a watercontent which permits the fiowability of the material comprised in thepulp. Since the water content thus introduced is also subject tocentrifugal force conditions, it can be understood that there would be atendency for this water content to be gradually eliminated throughgravity and the centrifugal force action, thus tendin to render the pulpless mobile as the water is passed from the pulp. To retain suchmobility, provision is made to introduce a new supply of water to theinterior of the drum so that the fiowable pulp characteristic will bemaintained. However, this addition tends to render the pulpcharacteristic of a cleaner type, since the removal of the liquid willalso tend to remove what are known as the slimes produced by the dirtand similar content of the pulp-since the added water is free of suchslime-component conditions, the pulp becomes clearer and cleaner.

In addition, this water supply also serves to arrest the length ofmovement of the riffie-borne content so as to confine the active actionof the apparatus to the zone above indicated as the quadrant. At the 90degree angle, the sides of the grooves incline downwardly, as indicatedin Figure 15, so that the introduction of the water will cause thecontent of the rifile to readily move out of the riffle over the lowerside of the groove so that further upward travel of the content will be26 arrested, even though such content be under centrifugal forceactivity at the time.

In addition to the above, the water delivery apparatus is so arranged asto tend to aid in the advance of particles from one convolution to thenext, by causing the water to be delivered in a path that is inclinedforwardly toward the bottom or nadir point of the drum, so that there isa tendency to cause particles moving over the side of the groove to movein a direction toward the advance convolution.

As shown in Figure 4, the hollow drum shaft 36 is provided internallywith a hollow shaft 59 which is coaxial with and of greater length thansaid shaft 38, shafts 3D and. 59 being suitably supported and capable ofindependent movement about their axes. The ends of shaft 59 are closedby suitable end walls 66 and 60a, these walls being adapted to support agroup of pipes 6lthree in number-which extend beyond both of such endwalls, the pipes being arranged more or less symmetrically with respectto the axis of shaft 59. As presently explained, the rear ends of pipes6| are controllably connected with a source of water supply, while theportions of the pipes in front of end wall 69a project into the interiorof the drum, the length of projection differing with the three pipes, asindicated in Figure 1. Each of the pipes includes a portion whichextends laterally and then forwardly to produce a nozzlecarrying sectionBla of a desired length. These sections Sta are designed to extend inalinement toward the large end of the drum, and since the pipes 61 leaveend Wall 63a at different points, the laterally extending portions mayextend at different angles in order to bring the sections Bla into thedesired alinement, the latter being indicated in Figure 5 with thealinement more or less parallel with the conical wall of the drum asshown in full lines in such figure.

Each of sections 6m carries a plurality of nozzles 62. As indicated,each nozzle has a generally triangular contour at its discharge end witha stem section 52a threaded to permit ready mounting on its section em.The triangular portion of the body of the nozzle includes an open-endedcasing $3 of triangular contour on the face, and is of decreasingdimensions away from such face to an intermediate point which presents aperforated diaphragm structure 6 3 which separates a chamber 62b of thestem from the interior of the casing 63, such interior end of thechamber being connected by one or more perforations 6M.

6'5 indicates a member located within the interior of casing 63, saidmember having its contour triangular, with the bottom wall located onthe bottom wall of the casing, but with the sides of the triangle spacedfrom the interior of the corresponding sides of the casing; the face ofthese sides of the member extend in parallelism with the correspondingsides of the casing. This spacing permits of the delivery of water fromthe interior of the casing through the front of the nozzle in the formof a stream, the outlines of which are practically an inverted V, thebottom being closed through the contact of the bottom of the member withthe bottom of the casing. Member 55 is designed to be adjustably mountedfor longitudinal movement Within the casing by means of a threadedelement fit extending through the member and adapted to be threaded intoan opening carried by diaphragm 64 as shown more particularly in Figure6. Threading of the element 66 causes the member 55 to move

